Seventy-five years ago this month, my great uncle, Alfred Siegbert Cohen, was murdered by Nazis at the Chelmno extermination camp. They poisoned and suffocated him by diverting exhaust fumes into a hermetically sealed truck while he was locked inside. He was 18 years old.

Alfred was born in Hamburg, Germany, on Boxing Day 1923. Ten years and one day earlier (Christmas Day 1913), Alfred’s older brother, my grandfather, Werner Josef Cohen, was born in Hamburg.

After finishing high school in 1931, Werner completed a commercial apprenticeship and went to work at a local paint shop. However, when the company he worked for “Aryanized,” it terminated his employment.

With no hope to make a life for himself, Werner started the process to leave Germany — his home and the home of generations of his (and my) ancestors — and immigrate to Palestine. Unfortunately, he ultimately was denied passage to Palestine because of a heart condition. He remained in Nazi Germany, working at a Jewish grocery store and as a mechanic.

On Nov. 10, 1938 — Kristallnacht — Werner was arrested on the streets of Hamburg. Along with 6,000 other Jewish men, he was sent to the Sachsenhousen concentration camp, outside Berlin. He was assigned prisoner number 10791, which was tattooed on his arm.

While in the camp, he was humiliated and dehumanized. If he was unable go to the bathroom on demand, he would be pushed into a pit of human feces. The Nazis forced Werner into hard, pointless labor; he was required to carry stones and other debris in barrels up a hill, hour after hour, day after day. As he did this, women and children would scream at him, making jokes, laughing, calling him names and throwing stones at him.

Werner was able to get out of the concentration camp and secure passage out of Germany. He eventually made it to Shanghai, China, where he survived the Japanese occupation and Allied bombings. In February 1948, Werner boarded a ship full of pumpkins bound for San Francisco as a stateless refugee. He immediately moved to Pittsburgh, where he had been promised a job in the paint industry that never materialized.

Werner soon married and had eight children, including my father. He started a carpentry business and lived the rest of his days in Pittsburgh. Werner died on April 13, 1977, less than two weeks before I was born. I am his namesake.

Starting in 1940, while Werner was in Shanghai, his father, Gustav Joseph Cohen, was forced into labor by the Nazis. He attempted to escape from Germany and follow his son to China. He was approved to leave, but was denied exit from Germany, apparently because he attempted to take some belongings the Nazis deemed too valuable with him.

On Oct. 25, 1941, Gustav, his ex-wife, Martha Cohen, and his son, Alfred, were deported to the Lodz ghetto. They all survived the seven-day transport, but a few months later, on Feb. 12, 1942, Martha died in the harsh conditions, presumably of starvation. Gustav died two-and-a-half weeks later. Alfred survived cold, hunger and infectious disease for six months following his father’s death. He was then sent to Chelmno, where he was murdered in the back of that truck.

I write this because, when we say “never again,” that means we must face with open eyes the horrors of the human capacity. We must acknowledge what we are capable of doing. And we must fight these impulses with everything that we have.

When people are in need, we must provide shelter. When people (especially leaders) attempt to divide us based on our race, ethnicity, religion, sexual orientation, gender identity or national origin, we must speak out and forcefully reject their hatred.

We are in scary times. Our worst impulses are pulling us apart. Don’t bother mouthing the words “never again” unless you are willing to do everything in your capacity to fight oppression in all of its forms.

On the 75th anniversary of my Great Uncle Alfred’s murder, I traveled across the state to help start an immigrant rights coalition in West Virginia. I spent that day thinking of my grandfather, a refugee who sought safety for nearly 15 years before making it to the United States. I thought of my great-grandfather, who attempted to immigrate only to be turned away and eventually killed. And I thought of my great uncle and the scores of other relatives whose lives were not valued by the world and were sentenced to death because they were “the other.”

Then I thought about the Syrian refugees who are just like my grandfather, and the immigrants who have come here for a better life, just like so many of my other relatives, and the DACA recipients who are just like me. And I thought about how we have turned our backs on all of these people.